Andrew Vickers, PhD, examines how Gleason Pattern 4 quantification may replace traditional Gleason scoring in the treatment of prostate cancer. He highlights potential benefits for standardization, reproducibility, and clinical decision-making, while emphasizing the need for validation.
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Andrew Vickers, PhD, discusses the need for reforming the Gleason score, the cornerstone of decision-making in prostate cancer management.
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Andrew J. Vickers, PhD, discusses the weaknesses of Gleason scoring in diagnosing localized prostate cancer. Dr. Vickers begins by differentiating between Gleason “scoring” and Gleason “grading,” explaining that Gleason grading is robust, while scoring is not as robust. He emphasizes that Gleason Grade Groups 2 through 4 depend on the ratios of tissue with various Gleason scores, which he asserts make little sense.
Dr. Vickers offers clinical examples to support his assertion and explains that, with patients with Gleason Grade Group 2 disease, the total length of biopsied tissue with a Gleason score of 4 is strongly predictive of adverse surgical pathology risk. Dr. Vickers explains that in patients with Gleason Grade Group 2 disease, the amount of tissue with a Gleason score of 3 is not predictive. Dr. Vickers shares data out of France that indicate that the amount of Gleason score 4 or 5 tissue is more predictive of biochemical recurrence (BCR) and metastasis than total Gleason score.
Dr. Vickers asserts that there is a need for urologic oncologists to find a replacement for the Gleason score as the dominant influence on decision-making in localized prostate cancer. Dr. Vickers emphasizes the value of focusing on tumor size and tissue quality in disease assessment, as is done with other cancers.
Read MoreAndrew J. Vickers, PhD, Attending Research Methodologist at Memorial Sloan Kettering Cancer Center in New York City, asserts that the current diagnostic use of MRI-targeting leads to overdiagnosis and overtreatment. He begins by stating that methods of detection such as systematic biopsies and measuring prostate-specific antigen (PSA) don’t tend to lead to underdiagnosis and undertreatment. To illustrate the reasons MRI-targeting leads to overdiagnosis and overtreatment, he displays data showing that in MRI-targeted biopsy the method of grading the core samples leads to higher grading of overall disease. Dr. Vickers points out that Gleason grade is not an inherent property of a tumor, but is instead a surrogate outcome. He then illustrates that biochemical recurrence (BCR) risk and risk of death for high-grade cancer on surgical pathology is dramatically reduced for clinically low-risk patients. Dr. Vickers cites the PRECISION trial which indicated that the MRI-targeted biopsies found far fewer low-grade cancers and more high-grade cancers, but the overall number of cancers identified was essentially the same. Dr. Vickers asserts that these results are consistent with a scenario whereby the technique simply characterized some of the low-grade cancers as high-grade. He then cites another study during which patients had both a systematic and an MRI-targeted biopsy; the MRI targeting identified more cancers that, in turn, led to more treatment. Dr. Vickers suggests this is problematic and opines that urologists do not need to find high-grade cancer in men with low-grade cancer on systematic biopsy. He supports his assertions by citing another study that followed 2,907 men for 17 years. Of those men, there were five cases of metastasis, with just two being potentially preventable. He also cites the European Randomized Study of Screening for Prostate Cancer (ERSPC) Rotterdam study which followed over 3,000 men with a negative sextant biopsy for 11 years and recorded just seven (.02 percent) deaths during that time. Dr. Vickers concludes that the number of men whose prostate cancer would have to be identified and treated in order to save one life is very large and MRI-targeting is leading to excessive overdiagnosis and overtreatment. Dr. Vickers then states that while there should be a clear clinical indication for MRI, such as negative biopsy with rising PSA, the current National Comprehensive Cancer Network (NCCN) guidelines call for treatment irrespective of the method of detection. Dr. Vickers concludes there is an urgent need for more restrictive use of MRI-targeting, evolved treatment guidelines for MRI-detected tumors, and additional research on oncologic risk of MRI-detected tumors.
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